Df140 using fuel

[akwolfman]

My new 140 uses more fuel than my old Sx150 fuel injected Yamaha.
It takes 4,000 rpm to get my 22ft Pacific Skiff on step.
When i did the 20hr maintance the oil had a funny look to it.
I also changed the spark plugs the motor smoked blue/black.
When i run at what people tell me 6,000 rpm i can watch the fuel in the candrop like made. I have tried running at different rpms but no change.
With gas at $4.79 a gal right now and might go back up when the last fuel barge get here. Any help welcome Thanks.

[150aintenuff]

something is wrong....what color are the plugs?????

[theoldwizard]

My new 140 uses more fuel than my old Sx150 fuel injected Yamaha.
It takes 4,000 rpm to get my 22ft Pacific Skiff on step.
When i did the 20hr maintance the oil had a funny look to it.
I also changed the spark plugs the motor smoked blue/black.
When i run at what people tell me 6,000 rpm i can watch the fuel in the candrop like made. I have tried running at different rpms but no change.
With gas at $4.79 a gal right now and might go back up when the last fuel barge get here. Any help welcome Thanks.
Early Yamaha F115 (and the Merc equivalent) had issues with running too rich/too cold or extended low speed (trolling) that would result in raw gas washing into the oil tank. The general term as "making oil" because the oil tank would be overfull.

Some engines got a new thermostat, some got new software. All were told to use dino oil for the break in (before switch to a synthetic) and "run 'em hard !" :D

Never heard of this problem with the Suzuki I4's

[akwolfman]

I used Delo 400 for the break -in and still using it. With the prop that came with it I had to run the motor in higher revs than the book said.
I will check the plugs later tonight when i get it ready for the run to fishcamp tommorrow. Had to go from 21 to a 23 pitch prop to keep it from hitting 6400 rpm and setting of the rev limiter. I also ordered the hotter thermostat so i'll put it in.With the old 150 i could get roughly 38 mile to a 6 gal of gas so this motor has been a big disapointment for fuel milage.
Thks.

[150aintenuff]

I used Delo 400 for the break -in and still using it. With the prop that came with it I had to run the motor in higher revs than the book said.
I will check the plugs later tonight when i get it ready for the run to fishcamp tommorrow. Had to go from 21 to a 23 pitch prop to keep it from hitting 6400 rpm and setting of the rev limiter. I also ordered the hotter thermostat so i'll put it in.With the old 150 i could get roughly 38 mile to a 6 gal of gas so this motor has been a big disapointment for fuel milage.
Thks.

doesnt the book require 10/30 in that motor........... delo 400 is 15/40... and in colder climates that isnt exactially great for an engine...

[akwolfman]

Using the delo 400 10/30 in the engine and there are different vescositys of it.. The plugs were the normal color but will check again after tommorrow.

[150aintenuff]

the plugs on that motor should be light ash brown/grey, almost an off white or creamy color definatly no darker than lunch bag tan...... any darker towards brown or black and you have an issue

[bigshrimpin]

Somethings are not adding up.

You said that you had to run 4000rpm to get on a plane
and the motor would turn 6400 with a 21 pitch.

4000rpm @ 2.59 ratio with a 21 ptich prop is 30mph (with 10% slip)
4000rpm @ 2.38 ratio with a 21 ptich prop is 32.9mph (with 10% slip)

Is the bottom of your boat is covered in barnacles??

[bigshrimpin]

Somethings are not adding up.

You said that you had to run 4000rpm to get on a plane
and the motor would turn 6400 with a 21 pitch.

4000rpm @ 2.59 ratio with a 21 ptich prop is 30mph (with 10% slip)
4000rpm @ 2.38 ratio with a 23 pitch prop is 32.9mph (with 10% slip)

Is the bottom of your boat is covered in barnacles??

20mph (just getting up on a plane ) with a 2.38 ratio / 23 Pitch Prop would be 45.3% slip . . . That's Horrible . . .

I think that the problem is with your setup or hull . . . not with the motor.

[akwolfman]

In Bush Alaska we do not have barnacles. Yes i have to turn 4,000 rpm
with both the 21,and 23 pitch prop to get it on step. The plugs were white on the electrodes and dark brown every where else. The bottom of the boat is the same as when i had the old 150 on it. The motor is sitting where the 150 sat. With the 23 pitch prop i only got 5,800 to 5,900 full throttle with a light load.

[bigshrimpin]

what's your GPS speed at 4000rpm and at 5900rpm?
Are you running the 2.38 or the 2.59 lower on that 140?

[akwolfman]

It is a 2007 with the lower gear ratio. When i tried a Turning point 23 pitch prop I could get 38 mph by gps. I could not get the reading a 4,000rpm because of traffic. Forgot to bring the gps on this last run but will have a few more runs in a few days. Thanks for all the info to check out.

[bigshrimpin]

2.59 w/23pitch @ 5900rpm . . . 38mph would be 24% slip.
2.59 w/23pitch @ 4000rpm . . . 20mph would be 40% slip.

I think you could reduce those slip numbers quite a bit.
Your setup is at least one of the problems.

Where does the cavatation plate line up?
Do you have trim tabs?
What diameter prop are you running?
Is the prop dinged up?

[akwolfman]

The cavatation plate is about a 1/4 in below the bottom of the boat.
No trim tabs. I now have a Suzuki 14by23 prop on it and is brand new.
Have tried a Turning point prop on 13 1/4 by 23 prop. I might have another run on the river but our temp are in the mid to lower 30s.